The present invention relates to a fabrication process and the structure of a semiconductor (solid-state) acceleration sensor or transducer.
In a conventional process, a semiconductor beam (such as a silicon cantilever) of an acceleration transducer is formed by etching from the backside of the sensor chip while the piezoresistive transducing element is formed by doping from the topside. Therefore, the conventional fabrication process requires a double side alignment technique, which is difficult to carry out and inaccurate. Moreover, the thickness beam is changed abruptly at each of the supported end of the beam and the movable end of the beam, so that the conventional acceleration transducer is susceptible to stress concentration and impact damage.